What is the longest word that can be spelled without repeating a letter?

Uncopyrightable is the longest word that can be written without repeating a letter. It is 15 letters long. The word means something for which one cannot obtain a copyright. For example, idiomatic expressions such as "pot calling the kettle black" and "with a pinch of salt" are so much a part of language that it is impossible to restrict their general use.

Here are some more interesting words:

Sucontinental is the only English word where the vowels are arranged from back to front, as u-o-i-e-a.

Latchstring is the English word for most consecutive consonants while queuing is the only English word where vowels are placed one after another five consecutive times.

The word strengths contains only 'e' as a vowel and is the longest word with just a single vowel in English.